I noticed on Stack Exchange that if an answer to a question is accepted, it is always first when sorting the answers by oldest - even if it wasn't the first answer.
Is that by design? Doesn't it break with the very point of sorting by oldest/newest?
(One example side-effect: when sorting by oldest to give rep to the one who provided a duplicate answer first, you're intuitively assuming the accepted one was first unless explicitly checking via mouse-over as noted by retracile.)